The aim of this randomized controlled trial (RCT) is to evaluate the impact and mechanisms of the Durham Connects (DC) brief universal nurse home-visiting program to prevent child maltreatment and improve child well-being. It is the first-ever RCT of a home-visiting program that is designed to prevent child maltreatment in an entire community population. Between July 1, 2009, and December 31, 2010, every infant born in Durham on an even birth date (n = 2,329) was assigned to receive the DC Program through the Durham County Health Department. Every infant born on an odd birth date (n = 2,451) received other services as usual and was assigned as control. The program has shown strong evidence of high penetration at the community level, reliable assessment of risk factors, successful connection of families with community services, and high family- consumer satisfaction. At age 6 months, intent-to-treat analyses indicate positive impact of random assignment to DC on receipt of community resources, well-baby pediatric care, high-quality childcare, blinded ratings of parental responsively, and parenting practices. The proposed study will follow families of children from age 30 months to 66 months. Administrative records will evaluate impact of random assignment to DC on child maltreatment cases, emergency room maltreatment-related injuries, and pediatric care. In-home interviews and blinded observations will assess parental functioning and child well-being in an already-recruited representative random sample of families from intervention (n = 269) and control (n = 280) birth dates. Data analyses of the population and representative samples will test four hypotheses: 1) Random assignment to the DC Program (that is, being born on an even birth date) will be associated with lower rates of child maltreatment and emergency department maltreatment-related injuries, better pediatric care, better parental functioning, and better child well-being than assignment as control (born on an odd birth date); 2) Intervention effect sizes will be larger for higher-risk groups; 3) Communit resource use and enhanced family functioning will mediate the positive impact of DC on outcomes; and 4) Developmental processes in dysfunctional parenting and child behavior among the control group will conform to the model guiding the program. This proposal offers an urgent, time-constrained opportunity to evaluate the population impact and mechanisms of this innovative universal home-visiting program, without the financial burden of program delivery or sample recruitment. The project will contribute to public health by (1) evaluating the impact and mechanisms of a universal home- visiting program that aims to lower the population rate of child maltreatment in a cost-effective way; and (2) testing models of the development of maltreatment, dysfunctional parenting, and child behavior and well-being.